Automatic strapping machine

ABSTRACT

In an automatic strapping machine in which a strapping band is advanced in one direction in a guide to encircle an article and is then advanced in the opposite direction to engage the article, apparatus for increasing the tension in the band before the ends of the band are fastened together. The apparatus comprises a frame mounted for displacement in both directions along the path of movement of the band, feed rolls carried by the frame to engage the band in the path, drive means for rotating the feed rolls to advance the band first in the one direction and then in the opposite direction, and control means for operating the feed rolls and the frame. The control means causes the band to advance around the article in the first direction until the article is surrounded by the band, then clamps the leading end of the band upon encirclement of the article and interruption of the first means, then drives the feed rolls in the opposite direction and to cause the frame to be displaced along the path toward the article which arrests the feed rolls, and finally operates to forcibly displace the frame away from the article to apply additional tension to tighten the band around the article.

United States Patent [72] Inventors Masatoshi Takano No. 377 l-Iigashi Narashino-machi l-chome, Chiba-ken, Narmhino-shi; I-Iiroshi Arita, No. 135 Otake, Sanhu-gun, Chiba-ken, 0amiMachi; Hayao Omori, No. 13, ll-go. Oshima-machi, Ko-to-ku, Tokyo-To, Japan [2]] Appl. No. 774,711 [22] Filed Nov. 12, 1968 45 Patented May 11, 1971 [32] Priority Dec. 29, 1967 [33] Japan [31] 42/84512 [S4] AUTOMATIC STRAPPING MACHINE 3 Claims, 9 Drawing Figs.

[52] US. Cl 100/4, 100/26 [51] Int. Cl ..B65B 13/04 [50] Field ofSearch 100/4, 26

[56] References Cited UNITED STATES PATENTS 2,730,036 1 1956 Cheesman l00/26UX 3,116,681 1/1964 Van DeBilt 100/26 Primary ExaminerBi1ly J. Wilhite Attorney-Howson and Howson ABSTRACT: In an automatic strapping machine in which a strapping band is advanced in one direction in a guide to encircle an article and is then advanced in the opposite direction to engage the article, apparatus for increasing the tension in the band before the ends of the band are fastened together. The apparatus comprises a frame mounted for displacement in both directions along the path of movement of the band, feed rolls carried by the frame to engage the band in the path, drive means for rotating the feed rolls to advance the band first in the one direction and then in the opposite direction, and control means for operating the feed rolls and the frame. The control means causes the band to advance around the article in the first direction until the article is surrounded by the band, then clamps the leading end of the band upon encirclement of the article and interruption of the first means, then drives the feed rolls in the opposite direction and to cause the frame to be displaced along the path toward the article which arrests the feed rolls, and finally operates to forcibly displace the frame away from the article to apply additional tension to tighten the band around the article.

Patented May 11, 1971 5 Sheets-Sheet l INVENTORS. MASATOSHI TAKANO HIROSHI ARITA HAYAO OMORI ATTYS.

PM: May 11, 1911 5 Sheets-Sheet 2 FIG. 4

INVENTORS. MASATOSH I TAKANO HIROSHI ARITA B HAYAO OMORI ATT Y8.

Patented May 11, 1971 5 Sheets-Sheet 5 ATTYS.

Patented May 11, 1971 5 Sheets-Sheet 4 INVENTORS. MASATOSHI TAKA NO HIROSHI ARITA HAYAO OMORI ATTYS.

Patented May 11, 1971 3,577,909

5 Sheets-Sheet 5 INVENTORS. MASATOSHI TAKA'NO HIROSHI ARITA HAYAO OMORI ATTYS.

AUTOMATIC STRAPPING MACHINE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an apparatus for feeding and fastening a band and more particularly to an apparatus for plying, feeding and fastening a band adopted to an apparatus for plying, welding and cutting portions of a band after binding around an article to be strapped in an automatic strapping machine.

In the automatic strapping machine generally used, a band feeding and pulling back operation to bind around an article to be strapped with a band, is done with one or more than two driving rollers in such steps as to stop pulling back of a band by a driving roller after a band has been bound around an article to be strapped and then, the band is tightened by using a jaw or a roller for fastening the article strictly.

2. Description of the Prior Art I-Ieretofore, in the automatic strapping machine, each mechanism for a band feeding and pulling back, for a band pulling back and stopping and for a band fastening, has been constructed independently, so that the construction has been complicated and it has not only had much trouble to control or to manufacture, but also the construction has required a large capacity and the cost has become expensive.

The provision of the present invention will eliminate such difficulty and faults.

SUMMARY OF THE INVENTION Broadly stated, the present invention contemplates adopting a new and improved apparatus for feeding and fastening a band to an apparatus for plying, welding and cutting portions of a band in an automatic strapping machine which is efiicient and does not require a complex apparatus as the previous one had.

Moreover, the apparatus of the present invention is easy to adjust, simple to construct, cheap to manufacture and reliable in operation owing to a simple mechanism of a swinging frame which is turned by a circular curved groove of a cylindrical cam fixed to the head of a camshaft of the apparatus for plying, welding and cutting a band.

The movement of the swinging frame is transmitted to a jaw and a driving roller arranged thereon, contacting with a top roller adjustably on the upper surface of said driving roller, so as the band to be fed, pulled back, fastened strictly around the article to be strapped and accomplished the desired result with a small sized, light and simply constructed apparatus.

The object and advantages of the invention will become more readily apparent to persons skilled in the art from the following detailed specification and annexed drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational partially broken view of the apparatus contemplated herein;

FIG. 2 is a partially broken side view of the apparatus shown in FIG. 1;

FIGS. 3, 4 and 5 are illustrations of operations of the ap paratus contemplated herein;

FIG. 6 is a perspective view of a controlling system of a contact rod raising a jaw arranged in a guide block fixed to a side of an upper portion of a swinging frame;

FIG. 7 is a perspective view partially broken illustrating a relation between a swinging frame and a cylindrical cam;

FIG. 8 is an elevational summarized view of an automatic strapping machine embodying this invention;

FIG. 9 is a schematic diagram of suitable means for controlling the operation of the feed rolls and the swinging frame.

DETAILED DESCRIPTION A cylindrical earn 5 is fixed to a camshaft 4 at one end thereof, mounted laterally on a frame 3 arranged on a supporting plate 2 below a slidable table 1, a roller 11 is set in a curv- 75 ing circular groove 6 formed on a peripheral surface of the cylindrical cam 5, the roller being supported at an end of a shaft pin 10 provided on a side of a swinging frame 9 which is borne with a shaft 8 rotatably at its one end in a bearing 7 formed on the supporting plate 2.

While the pulley 11 being in a normal position at a neutral zone 12 in the groove 6 of the cam 5, the swinging frame 9 is kept inclined to the right loosely (the right in the drawing), while in a position wherein the roller ll being contacted with a right-turning portion 13 in the groove 6, the cylindrical cam 5 rotates in accordance with a rotation of the camshaft 4, and the swinging frame 9 turns further to the right until it becomes capable of turning to the left when the roller 11 comes to an enlarged turning portion 14 in the groove 6.

During the frame 9 being inclined to the left, the left side 15 (the left in the drawing) of the frame 9 contacts with a switch lever 18 of a limit switch 17 which is fixed to an apparatus body 16 for actuating the switch 17.

The swinging frame 9 is provided with a driving shaft 20 mounted on the upper part thereof, to one end of the shaft 20 a driving roller 21 is fixed, with the upper surface of the roller 21 contacts a top roller borne with a pivot 24 driven in a.

middle portion of one side of a control plate 23, a spindle 22 of which is borne at one end of the control plate 23 on the swinging frame 9, an upper fork end 27 of a screw rod 26 being pivoted by a pivot 28 at the end of the control plate 23, the screw rod 26 is inserted into a perforated hole 30 formed in a receiving portion 29 provided at the rear end (the right in FIG. 6) of the swinging frame 9; at the lower end of the screw rod 26 a control nut 31 is bolted and between the control nut 31 and the lower surface of the receiving portion 29 being furnished with a spring 32 which is adjusted by screwing or loosing the nut 31 so as the top roller 25 to be contacted with the driving roller 21 adjustably being controlled to be pressed each other closely or lightly; a pulley 33 fixed to the other end of the driving shaft 20 having the driving roller 21 fixed to one end thereof is connected through a transmitting belt 36. with one 35 of a double pulley 34 mounted rotatably on one end of the shaft 8 which supports the lower portion of the frame 9, while the other end 37 of the double pulleys 34 is connected through a transmitting belt 40 with a transmitting pulley 39 mounted on one end of a shaft 16 of a motor 38 arranged in the apparatus body 16, so as the driving roller 21 to be rotated normally or reversely in response to the positive or negative rotation of the motor 38.

Guide blocks 42, 43 having leading slots 41, 41 respectively for leading a hand through between the driving roller 21 and the top roller 25, are fixed to the upper side of the swinging frame 9 symmetrically on the opposite sides of the contacting peripheral surfaces of the rollers 21, 25; in the leading slot 41 of the guide block 43 is formed an upwardly expanded V- shaped concavity 44 wherein being provided a jaw 45, the lower end of which is pivoted by a pivot 46 on the guide block 43; between a side of the jaw and inside of the concavity 44 a spring 47 is furnished so as the jaw 45 to be pressed constantly to turn to the right side (the right in the drawing) of the concavity 44 while the upper surface 48 of the jaw 45 to be separated from the inside of the leading slot 41 for making an interval 49 to pass a band a and then the jaw 45 is raised against the spring 47 turning to the left in the drawing so as the upper surface of the jaw 45 to be pressed on the inside of the leading slot 41.

In the middle part of a side of the jaw 45 is set up a contacting pin 50 and at the right side (in the drawing) of the pin 50 is positioned an upper portion of a contacting rod 53 which is rotatably pivoted on a middle portion of a fixed board 51 with a pivot 52, vertically put on a supporting board 2 and a shaft pin 54 is inserted into the end portion of the contacting rod 53, being projected on the other side of the fixed board 51 through an arc-shaped slot 55 formed in the lower portion of the fixed board 51 centering around the pivot 52 around of which is wound a middle portion of a spring rod 56, one end 57 of which being fixed to the board 51, while the other end S8 is fixed to the contacting rod 53, the upper portion of which being pressed toward the contacting pin 50 of the jaw 45, while the lower portion of the rod 53 being pressed in the opposite direction and the shaft pin 54 inserted into the lower portion of the rod 53 being pressed constantly toward one end portion (to the right in the drawing) of the arc-shaped slot 55 in the fixed board 51; a pushing contact piece 61 at the head portion of an adjustable screw rod 60 screwed into a supporting projection 59 provided on the side of the fixed board 51 adjacent one end of the arc-shaped slot 55, is contacted with a side of an outwardly projected end of the shaft pin 54 being in a pressed condition.

The adjustable screw rod 60 is screwed with a thumb nut 62 fixed to the other end of the rod 60 to be moved forward and backward for pushing the shaft pin 54 to move it clockwise along the arcshaped slot 55 or returning it by moving counterclockwise against the action of the spring rod 56, thus, the interval between the contacting rod 53 and the contacting pin 50 of the jaw 45 is adjusted widely or narrowly as desired, so as the head portion of the guide block 42 projected from the side 15 of the swinging frame 9 to be encountered with one end of a band receiving inlet 63 arranged on the frame 3.

As may be seen in FIG. 9, when the limit switch 71 is operated upon contact of the switch lever 18, a circuit causing the negative motion of the motor 38 is opened to arrest rotation of the driving roller 21 and hence the backward pulling action on the band a while simultaneously closing a circuit of a motor M which is connected to the camshaft 4.

Now, operations of this invention contemplated should be made clear:

For adjusting the interval between the head portion of the contacting rod 53 and the contacting pin 50 of the jaw 45, by means of the screw nut 62, the adjustable screw rod 60 is screwed to be moved forward and backward, so as the position of the shaft pin 54 in the lower end of the contacting rod 53 being pressed by the action of the spring rod 56 against the pushing contact piece 61 on the head portion of the screw rod 60, to be changed as desired effecting that in a condition shown in FIG. 3, during the camshaft 4 being turned once, the head portion of a band fed, is set by a set rod (explained hereafter) at a lower surface of a slide table (explained hereafter) and the circuit connected to the motor M (illustrated in FIG. 9) transmitting the camshaft 4 is opened by a switch cam (explained hereafter) of the end of the camshaft 4, or in a condition shown in FIG. 4, during the camshaft 4 being stopped, the roller 11 mounted on the head portion of the shaft pin provided in the lower part of the swinging frame 9, is positioned in the enlarged left-tuming position of the curving circular groove 6 formed on the cylindrical cam 5, while the circuit of the motor 38 is switched to the negative motion, making the driving roller 21 rotate reversely as shown by an arrow in FIG. 3 to start a pulling back of the band a.

After an article to be strapped b (FIG. 8) having been wound by the band a, when the movement of the band a stops, the swinging frame 9 is raised moving to the side of the frame 3 (to the left in the drawing) by the action of the driving roller 21 which rotates the top roller 25.

When the roller 11 contacts with the left side (the left in the drawing) in the enlarged left-tuming portion 14 in the circular curving groove 6 as shown in FIG. 4, the side 15 of the swinging frame 9 pushes the switch lever 18 of the limit switch 17 fixed to the body 16, thus the circuit of a negative motion of the motor 38 is opened to stop the motor 38, while the circuit of another motor M (illustrated in FIG. 9) connected with the camshaft 4 through the limit switch 17, is closed, so as the camshaft 4 to be rotated during the driving roller 21 being stopped.

Thus, the roller 11 of the head portion of the shaft pin 10 provided on the lower portion of the swinging frame 9, is moved to the right-tuming portion 13 in the circular curving groove 6 formed on the cylindrical earn 5, while the swinging frame 9 is swung to the right in a large angle as shown in FIG. 5, and the upper portion of the contacting rod 53 which has been adjusted its position during the frame 9 being swung, contacts with the contacting pin 50 of the jaw 45 arranged on the guide block 43 provided on the upper portion of the swinging frame 9 and the jaw 45 moved toward one side of a concavity 44 (to the left in the drawing) against the spring 47 by means of the upper portion of the contacting rod 53 supported and pressed by the spring rod 56, so as the band a to be held firmly between the upper surface 48 of the jaw 45 and the inside of the leading slot 41, and pulled in accordance with a swing to the right of the swinging frame 9 and fastened tightly after the article b has been wound round by the band a.

While the upper portion of the contacting rod 53 being contacted with the contacting pin 50 of the jaw 45, turning to the right (the right in the drawing) together with the pin 50, is increased the pressure upon the pin 50 by the spring rod 56 in accordance with a swingof the frame 9, on the other hand, the shaft pin 54 is moved to the left in the arc-shaped slot 55 being apart from the pushing contact piece 61 of the adjustable screw rod 60, and the contact rod 53 is turned together with the swinging frame 9, pushing the jaw 45 to move so as the band a to be held tightly between the upper surface 48 of the jaw 45 and the inside of the leading slot 41 during the frame 9 being swung.

Now, the operations of the apparatus contemplated in this invention adopted to an automatic strapping machine with which it is connected, should be explained in detail with reference to FIGS. 1 and 8:

The apparatus of this invention is arranged adjacent to a frame 3 of the apparatus for cutting a welded and overlapped or plied band, having the camshaft 4 being supported thereon.

The roller 11 on the head portion of the shaft pin 10 inserted into a side of the swinging frame 9 is set in the circular curved groove 6 of the cylindrical cam 5 fixed to the camshaft 4. The end portion of the guide block 42 arranged at the upper part of the swinging frame 9 is opposed with the band leading inlet 63 fomted in the frame 3, so as the band a which is pulled out of the band feeding frame 64 to be led to the leading slot 41 of the guide block 43 arranged on the upper portion of the swinging frame 9 through guide rollers 65 and after the band has passed between the driving roller 21 and the top roller 25, the band a is led to the leading slot 41 of the guide block 42.

The driving roller 21 is rotated in the direction as shown by the arrow in FIG. 1, by switching the motor 38 to the positive motion through a transmitting pulley 39, a transmitting belt 40, a double pulley 34 (FIG. 2), a transmitting belt 36, a pulley 33 and the driving shaft 20, so as the band a which is being pressed on the driving roller 2.1 by the top roller 25 to be fed in accordance with the rotation of the driving roller 21 through the guide block 42 and the band leading inlet 63 being led to a passage 67 formed on the upper portion of the pushing rod 66, then, to a perforation 70 which is formed through an upper edge 69 of a guide wall 68 adjacent to one side of the pushing rod 66, the upper edge 69 being conformed to a part of a band cutter, and then through between the lower surface of a stopper 71 and the pushing rod 81 and between the slide table 1 and the stopping rod 72, into one end portion of a guide arch 74 which is led to a base 73 for mounting the article b to be strapped.

The band led to one end portion of a guide arch 74, goes around outer side of the article and is led to one side of the lower surface of the base 73 through the other end portion of the guide arch 74 and goes along the lower surface of the base 73, so as the head portion of the band a to be contacted with a microswitch 75 to open the circuit of the motor 38, until the band arrives at the lower surface of the slide table 1 by inertia and enters in a concavity in which a stopper 71 is arranged by which the band is stopped.

Then, the circuit of the motor (not shown in the drawing) connected with the camshaft 4 is closed to be rotated, so as the pushing rod 66 to be raised by the pushing cam 76 fixed to the camshaft 4, and the band to be pressed and stopped on the lower surface of the slide table 1 by the head of the pushing rod 66, while the switch cam 77 fixed to the camshaft 4 being rotated together therewith, acts on the limit switch 5 (shown in FIG. 9) so as the circuit of the motor M(also illustrated in FIG. 9)which is connected with the camshaft 4, to be opened and the cylindrical cam 5 which is fixed to the end of the camshaft 4 as shown in FIG. 4, stops during the roller being set in the left-tuming enlarged portion 14 of the circular curved groove 6, so as the swinging frame 9 to be turned to the left and the limit switch (see FIG. 9) to open the said circuit, closing the circuit of the motor 38 in a negative motion at the same time, accordingly, the driving roller 2] connected with the motor 38 turns reversely as shown by the arrow in FIG. 3 and begins to pull back the band during the camshaft 4 being at rest.

When the band a is bound around the article b to be strapped on the base 73, the movement of the band stops being held between the top roller 25 and the driving roller 21. Then, the swinging frame 9 turns to the leftas shown in FIG. 4 by a reaction of the rotation of the driving roller 21, so as the switch lever 18 of the limit switch 17 to be actuated by the side portion of the frame 9 to open the circuit of the motor 38 while it closes the circuit of the motor (illustrated in FIG. 9) connected with the camshaft 4, so as the driving roller 21 to be stopped and the camshaft 4 to be rotated during the pulling back operation of the driving roller 21 being stopped.

When the roller 11 on the head of the shaft pin 10 on the side of the swinging frame 9 is set in the right-tuming portion 13 of the circular curved groove 6 of the cylindrical earn 5 rotating together with the camshaft 4, the frame 9 turns to the right in a large angle as shown in FIG. 5, while the upper portion of the contacting rod 53 adjusted by the adjustable screw rod 60 pivoted to the fixed board 51, contacts with the contacting pin 50 of the jaw 45 arranged on the guide block 43 fixed to the upper portion of the frame 9 which is turning to the right, and the jaw 45 is operated to be raised against the spring 47, so as the band to be pressed on the inside of the leading slot 41 of the guide block 43 by the upper surface 48 of the jaw 45.

The band a, thus being held tightly at the upper portion of the frame 9, is continued to be fastened further, strapping the article b which has been once bound around in accordance with the turning movement of the swinging frame'9 to the right until the roller 11 is set in the right-tuming portion 13 of the circular curved groove 6 of the rotating cylindrical cam 5.

During the band being fastened, while the pulley 11 being set in the right-tuming portion 13 of the groove 6, a restraining rod 72, a heating plate (not shown in the drawing) and a repressing rod 81 are operated successively by a restraining cam 78 fixed to the camshaft 4, a heater cam 79 and a pressing cam 80 for the restraining the overlapped or plied portions of the band to be welded, before the band being cut' at the delivering side.

When the camshaft 4 turned once having finished a winding round of the band, strict fastening, plying up and welding of the parts of the band and cutting, the repressing rod 66, restraining rod 72, pushing rod 81 which are connected with the camshaft 4 come back downwardly to their positions, so as the roller 11 to be set in the neutral position 12 of the circular curved groove 6 of the cylindrical cam 5 and the swinging frame 9 to return to the neutral position as shown in FIG. 5, while the limit switch S provided in the circuit of the motor M (illustrated in FIG. 9) connected to the camshaft 4, is opened by the switch cam 82, so as the camshaft to be stopped to finish the strapping operation.

The slide table 1 moves from under the band a and the article b when plying up and welding of the parts of the band and cutting of the band, have finished, so as the strapped article to be removed from the base 73 for the next following operatrons.

Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claim.

We claim:

1. An apparatus for feeding and fastening a band, adopted to an apparatus for plying, welding and cutting parts of a band in an automatic strapping machine, including a swinging frame, the swinging movement of which being transmitted from a cylindrical cam; a driving roller connected with a motor, being arranged on the upper portion of said swinging frame; a top roller being pressed adjustably by and contacted with said driving roller; a pair of guide blocks having leading slots respectively for leading a band through between the driving roller and the top roller arranged on a side of the upper portion of said swinging frame; said pair of guide blocks being positioned symmetrically on the opposite sides of the contacted points of said rollers with each other; an upwardly expanded concavity being formed in one of said leading slot wherewith a jaw is provided, the lower end of which being pivoted on said guide block by a pivot on which said jaw is turned to one side in said concavity, constantly being pressed by a spring, while the upper surface of said jaw is separated from the inside of the leading slot for forming a space to pass a band; an upper portion of a contact rod being arranged on a fixed board adjustably with a spring rod aside of a contact pin which is inserted into a side of said jaw; a limit switch being fixed to a body of the apparatus to be switched by contacting with a side of said swinging frame turning toward said limit switch, thereby a circuit of a motor is opened to transmit a reverse rotation to the driving roller; said contact rod being contacted with the contact pin of the jaw to be raised, while said swinging frame is being turned by the rotation of said cylindrical cam, so as the upper surface of the jaw to cooperate with the inside of said leading slot of the guide block for holding an securing the band.

2. Apparatus for feeding and tightening a band in an automatic strapping machine comprising means to guide the band in a path to encircle the article to be strapped, a frame mounted for displacement along said path, feed rolls carried by said frame to engage the band in said path, drive means for said feed rolls operable to rotate said feed rolls in one direction to feed the band around the article and to rotate the rolls in the opposite direction to pull said band tight around the article, and control means for said drive means including a first means operable to drive said feed rolls in the one direction until said band encircles said article, a second means to clamp the leading end of said band upon completion of said encirclement and interruption of said first means, a third means operable upon operation of said clamping means to drive said feed rolls in the opposite direction; said feed rolls, upon tightening of the band around said article operating to displace said frame along said path toward said article; a fourth means operable in response to displacement of said frame to arrest said feed rolls; and a fifth means operable in response to the arrest of said feed rolls to forcibly displace said frame away from said article to thereby further tighten said band around said article.

3. Apparatus according to claim 2 including a jaw on said frame operable upon said displacement of the frame away from the article to clamp said band against said frame during the terminal portion of its travel away from said article. 

1. An apparatus for feeding and fastening a band, adopted to an apparatus for plying, welding and cutting parts of a band in an automatic strapping machine, including a swinging frame, the swinging movement of which being transmitted from a cylindrical cam; a driving roller connected with a motor, being arranged on the upper portion of said swinging frame; a top roller being pressed adjustably by and contacted with said driving roller; a pair of guide blocks having leading slots respectively for leading a band through between the driving roller and the top roller arranged on a side of the upper portion of said swinging frame; said pair of guide blocks being positioned symmetrically on the opposite sides of the contacted points of said rollers with each other; an upwardly expanded concavity being formed in one of said leading slot wherewith a jaw is provided, the lower end of which being pivoted on said guide block by a pivot on which said jaw is turned to one side in said concavity, constantly being pressed by a spring, while the Upper surface of said jaw is separated from the inside of the leading slot for forming a space to pass a band; an upper portion of a contact rod being arranged on a fixed board adjustably with a spring rod aside of a contact pin which is inserted into a side of said jaw; a limit switch being fixed to a body of the apparatus to be switched by contacting with a side of said swinging frame turning toward said limit switch, thereby a circuit of a motor is opened to transmit a reverse rotation to the driving roller; said contact rod being contacted with the contact pin of the jaw to be raised, while said swinging frame is being turned by the rotation of said cylindrical cam, so as the upper surface of the jaw to cooperate with the inside of said leading slot of the guide block for holding an securing the band.
 2. Apparatus for feeding and tightening a band in an automatic strapping machine comprising means to guide the band in a path to encircle the article to be strapped, a frame mounted for displacement along said path, feed rolls carried by said frame to engage the band in said path, drive means for said feed rolls operable to rotate said feed rolls in one direction to feed the band around the article and to rotate the rolls in the opposite direction to pull said band tight around the article, and control means for said drive means including a first means operable to drive said feed rolls in the one direction until said band encircles said article, a second means to clamp the leading end of said band upon completion of said encirclement and interruption of said first means, a third means operable upon operation of said clamping means to drive said feed rolls in the opposite direction; said feed rolls, upon tightening of the band around said article operating to displace said frame along said path toward said article; a fourth means operable in response to displacement of said frame to arrest said feed rolls; and a fifth means operable in response to the arrest of said feed rolls to forcibly displace said frame away from said article to thereby further tighten said band around said article.
 3. Apparatus according to claim 2 including a jaw on said frame operable upon said displacement of the frame away from the article to clamp said band against said frame during the terminal portion of its travel away from said article. 